High energy curable liquid polyene polythiol polymer composition

ABSTRACT

THE INVENTION DISCLOSED IS FOR A NEW HIGH ENERGY CURABLE LIQUID POLYMER COMPOSITION WHICH INCLUDES A LIQUID POLYENE COMPONENT HAVING A MOLECULE CONTAINING AT LEAST TWO UNSATURATED CARBON-TO-CARBON BONDS DISPOSED AT TERMINAL POSITIONS ON A MAIN CHAIN BACKBONE OF THE MOLECULE AND A POLYTHIOL COMPONENT HAVING A MOLECULE CONTAINING A A MULTIPLICITY OF PENDANT OR TERMINALLY POSITIONED -SH FUNCTIONAL GROUPS PER AVERAGE MOLECULE. THE HIGH ENERGY CURABLE LIQUID POLYMER COMPOSITION UPON CURING IN THE PRESENCE OF HIGH ENERGY IRRADIATION FORMS ODORLESS, SOLID, ELASTOMERIC PRODUCTS WHICH MAY SERVE AS SEALENTA, COATINGS, ADHESIVES, AND MOLDED ARTICLES.

United States Patent Office 3,725,228 Patented Apr. 3, 1973 3,725,228HIGH ENERGY CURABLE LIQUID POLYENE- POLYTHIOL POLYMER COMPOSITIONClifton L. Kehr, Silver Spring, and Walter R. Wszolek, Sykesville, Md.,assignors to W. R. Grace 8: Co., New York, NY.

No Drawing. Application June 23, 1970, Ser. No. 49,191,

which is a continuation-in-part of abandoned application Ser. No.617,801, Feb. 23, 1967, which in turn is a continuation-in-part ofabandoned application Ser. No. 567,841, July 26, 1966. Divided and thisapplication June 25, 1971, Ser. No. 156,975

Int. Cl. C08c 11/54; C08d 1/00; C08f 1/16 U.S. Cl. 204-15914 17 ClaimsABSTRACT OF THE DISCLOSURE The invention disclosed is for a new highenergy curable liquid polymer composition which includes a liquidpolyene component having a molecule containing at least two unsaturatedcarbon-to-carbon bonds disposed at terminal positions on a main chainbackbone of the molecule, and a polythiol component having a moleculecontaining a multiplicity of pendant or terminally positioned SHfunctional groups per average molecule. The high energy curable liquidpolymer composition upon curing in the presence of high energyirradiation forms odorless, solid, elastomeric products which may serveas sealants, coatings, adhesives, and molded articles.

The present application for U.S. Letters Patent is a division of Ser.No. 49,191, filed June 23, 1970, which in turn is a continuation-in-partof copending application Ser. No. 617,801, filed Feb. 23, 1967, nowabandoned, which in turn is a continuation-in-part of application Ser.No. 567,841, filed July 26, 1966, now abandoned.

This invention relates to a new high energy curable liquid compositionwhich includes a liquid polyene component having a molecule containingat least two unsaturated carbon-to-carbon bonds disposed at terminalpositions on a main chain of the molecule, a polythiol component havinga molecule containing a multiplicity of pendant or terminally positionedSH functional groups per average molecule, and a photocuringrateaccelerator.

It is well known in the art that cure of internally unsaturated polymerssuch as polybutadiene or polyisoprene may be effected with polythiols.However, such polymers, due mainly to residual internal unsaturationafter curing, are unstable either to thermal oxidation or ultra-violetcatalyzed oxidation, and are subject to rapid attack by ozone.Eventually degradation and embrittlement results in the internal doublebond polymers, substantially reducing their useful service life.

A limitation of commercially available liquid polyurethane prepolymersis the fact that they are terminated by isocyanate (NCO) groups. TheseNCO groups are extremely unstable in storage, and are highlywater-sensitive such that under practical conditions, they react withtraces of moisture from the atmosphere to form gaseous carbon dioxideand amino groupings which in turn react with more NCO to form eventuallya highly viscous,

sometimes completely insoluble urea-extended chain network. In caseswhere insolubilization occurs, the polymer has to be discarded at greatexpense. Further, if the NCO-terminated prepolymers come in contact withtraces of either acidic or basic impurities, dimerization and/ortrimerization of the NCO functions may take place to form viscous,sometimes insoluble products during storage. Even mild alkalis such asthose constituents normally present on the surface of glass vessels andcontainers may cause storage problems.

A further limitation for some applications is found in polyurethanepolymers of the prior art which are derived from aromatic diisocyanatesor polyisocyanates such as tolylene-2,4-diisocyanate,tolylene-2,6-diisocyanate, 4,4'-diisocyanatodiphenylmethane, and thelike. These aromatic diisocyanates (or mixtures thereof) enjoywidespread use in polyurethane elastomers, foams, and coatings, becauseof their ready commercial availability, high degree of reactivity andrelatively low cost. The derived polyurethane products, however, areknown to turn yellow, amber, orange or brown in color when exposed tosunlight, ultraviolet light or other forms of actinic radiation. Thisyellowing tendency imparts a definite limitation on the usage of suchpolyurethanes in many applications. There is evidence in the technicalliterature that shows that this yellowing or discoloration problem isdirectly attributable to the aromatic (benzenoid) nucleus in thearomatic diisocyanates, and accordingly serious yellowing problems inpolyurethanes may be avoided by use of aliphatic polyisocyanates such ashexamethylene diisocyanate. These aliphatic polyisocyanates, however,are difiicult to manufacture, are relatively expensive and arerelatively slow in reaction rate during polymer formation reactions incomparison to the aromatic polyisocyanates.

The use of polymeric liquid polythiol polymers which are cured to solidelastomeric products by oxidative coupling of the thiol (SH) groups todisulfides (--S-S groups) are known in the sealants, coatings andadhesives field. Oxidizing agents such as PM); are commonly used toefiect this curing reaction. These mercapto-containing compounds,however, both before and after curing with PbO type curing system yieldelastomeric compositions with an offensive odor which limits theirusefulness generally to outdoor service. Thus, oxidatively-curedmercapto polymer systems have found restricted commercial acceptance dueto their offensive odors.

A limitation of commercial liquid polymeric sealants and coatings isfound in one-package systems. All the compounding ingredients, includingthe curing agents, are blended together and charged into a tightlysealed container until used. -In these commercial sealants(polysulfides, polydisulfides, polymercaptans, polyurethanes andpolysilicones), the curing reaction of one-package systems is initiatedby moisture (H O) from the air. The moisture-curable systems leavesomething to be desired because the moisture content of the air varieswidely. Hence, the curing performance of moisture-curable adhesives,coatings and sealants is variable and is difficult to predict andcontrol. In the case of polyurethanes a further disadvantage ofmoisture-curable systems is observed. In the curing reaction (NCO groupsreacting with H O), a volatile gas (carbon dioxide) is liberated andthis evolved gas tends to cause unsightly and propertyweakening gaspockets or voids in the final product.

It has now been found that numerous defects of the prior art may beeffectively overcome by practice of the present invention which providesa new high energy curable liquid composition which contains particularpolyenes which are curable to solid resins or elastomers. For example,when urethane-containing polyenes are compounded with polythiols, theprepared composition may be stored safely for long periods of time inthe absence of high energy bombardment. Upon exposure to high energybombardment such as high energy electrons, the prepared system may becured rapidly and controllably to a polythioether-polyurethane productwhich is low in cost and equal or better in reaction rate in polymerformation when compared with compositions derived from conventionaltechnology.

Generally stated, the present invention provides a high energy curablecomposition which comprises a particular polyene component and apolythiol component.

The polyene component may be represented by the formula wherein m is aninteger of at least 2, and X is a member selected from the groupconsisting of:

In the groups (a) to (e), f is an integer from 1 to 9; R is a radicalselected from the group consisting of hydrogen, fluorine, chlorine,furyl, thienyl, pyridyl, phenyl and substituted phenyl, benzyl andsubstituted benzyl, alkyl and substituted alkyl, alkoxy and substitutedalkoxy, and cycloalkyl and substituted cycloalkyl. The su'bstituents onthe substituted members are selected from the group consisting of nitro,chloro, fluoro, acetoxy, acetamido, phenyl, benzyl, alkyl, alkoxy andcycloalkyl. Alkyl and alkoxy have from 1 to 9 carbon atoms andcycloalkyl has from 3 to 8 carbon atoms.

The members (a) to (e) are connected to [A] through divalent chemicallycompatible derivative members. The members (a) to (e) may be connectedto [A] through a divalent chemically compatible derivative members ofthe group consisting of Si(R) carboxylate, sulfone, -O,

alkyl and substituted alkyl, cycloalkyl and substituted cycloalkyl,urethane and substituted urethane, urea and substituted urea, amide andsubstituted amide, amine and substituted amine, and aryl and substitutedaryl. The alkyl members have from 1 to 9 carbon atoms, the aryl membersare either phenyl or naphthyl, and the cycloalkyl members have from 3 to8 carbon atoms with R and said members substituted being defined above.B is a member of the group consisting -O--, -S, and NR-.

The member [A] is polyvalent; free of reactive carbon-to-carbonunsaturation; free of highly water-sensitive members; and consisting ofatoms selected from the group consisting of carbon, oxygen, nitrogen,chlorine, bromine hydrogen, fluorine, phosphorus and silicon.

The polyene component has a molecular weight in the range from about 64to 20,000, preferably about 200 to about 10,000, and a viscosity in therange from essentially 0 to 20 million centipoises at C. as measured bya Brookfield viscometer.

The polythiol component has a molecular weight in the range from about50 to about 20,000 and the general formula:

at- E wherein R is a polyvalent organic moiety free from reactivecarbon-to-carbon unsaturation and n is at least 2. The ene/thiol moleratio is selected so as to provide a solid, self-supporting curedproduct under ambient conditions when exposed to high energybombardment.

More particularly, the member [A] of the polyene composition may beformed primarily of alkyl radicals, phenyl and urethane derivatives,oxygenated radicals, and nitrogen substituted radicals. The member [A]may also be represented by the formula:

wherein i and k are integers greater than 1; R is a member of the groupconsisting of hydrogen, and alkyl having 1 to 9 carbon atoms; R is amember of the group consisting of hydrogen, and saturated alkyl having 1to 9 carbon atoms; R is a divalent derivative of the group consisting ofphenyl, benzyl, alkyl, cycloalkyl, substituted phenyl, substitutedbenzyl, substituted alkyl and substituted cycloalkyl; with the termsalkyl, cycloalkyl and members substituted being defined above.

General representative formulas for the polyenes of the presentinvention may be prepared as exemplified in the following.

IIIPly(alkylene-ether)poly0l reacted with polyisocyanate and unsaturatedmonoalcohol forming polyurethane polyenes and related polymersDifunctional ilrliunetloual (LP; (balk-wheel Tetraiunetional In theabove formulas, the sum x-l-y+n in each chain segment is at least 1; Pis an integer of 1 or more; q is at least 2; n is at least 1; R isselected from the group consisting of hydrogen, phenyl, benzyl, alkyl,cycloalkyl, and substituted phenyl; and R is a member of the groupconsisting of CH: CH \Clh/n hydrogen, phenyl, cycloalkyl, and alkyl.

The novel class of polyenes of this invention derived from carbon tocarbon unsaturated monoisocyanates may be characterized by extreme easeand versatility of manufacture when the liquid functionality desired isgreater than about three. For example, consider an attempted synthesisof a polyhexene starting with an --OH terminated polyalkylene etherhexol such as Niax Hexol LS490 (Union Carbide Corp.) having a molecularweight of approximately 700, and a viscosity of 18,720 cps. at C. Anattempt to terminate this polymer with ene groups by reacting one moleof hexol with 6 moles of tolylene diisocyanate (mixed-2,4, -2-6-isomerproduct) and 6 moles of allyl alcohol proceeded nicely but resulted in aprematurely chain extended and crosslinked solid product rather than anintended liquid polyhexane. Using the monoisocyanate route, however,this premature chain extension may be avoided and the desiredpolyurethanecontaining liquid polyhexene may be very easily prepared bya simple, one-step reaction of one mole of hexol with 6 moles of allylisocyanate. This latter polyhexene has the added advantage of beingcured using the teachings of this invention to a non-yellowingpolythioether polyurethane product. Similarly, the unsaturatedmonoisocyanate technique may be used to prepare liquid polyenes fromother analagous highly functional polyols such as cellulose, polyvinylalcohol, partially hydrolyzed polyvinyl acetate, and the like, andhighly functional polyamines such as tetraethylene pentamine,polyethyleneimine, and the like.

N yi

A general method of forming one type of polyene containing urethanegroups is to react a polyol of the general formula R t-OH) wherein R isa polyvalent organic moiety free from reactive carbon-tocarbonunsaturation and n is at least 2; with a polyisocyanate of the generalformula R {-NCO) wherein R is a polyvalent organic moiety free fromreactive carbon-to-carbon unsaturation and n is at least 2 and a memberof the group consisting of an ene-ol, yne-ol, cue-amine and yne-amine.The reaction is carried out in an inert moisture-free atmosphere(nitrogen blanket) at atmospheric pressure at a temperature in the rangefrom 0 to about C. for a period of about 5 minutes to about 25 hours. Inthe case where an ene-ol or yne-ol is employed, the reaction ispreferably a one step reaction wherein all the reactants are chargedtogether. In the case where an ene-amine or yne-amine is used, thereaction is preferably a two step reaction wherein the polyol and thepolyisocyanate are reacted together and thereafter preferably at roomtemperature, the cue-amine or yne-amine is added to the NCO terminatedpolymer formed. The group consisting of ene-ol, yne-ol, ene-amine andyne-amine are usually added to the reaction in an amount such that thereis one carbon-tocarbon unsaturation in the group member per hydroxylgroup in the polyol and said polyol and group member are added incombination in a stoichiometric amount necessary to react with theisocyanate groups in the polyisocyanate.

A second general method of forming a polyene containing urethane groups(or urea groups) is to react a polyol (or polyamine) with anene-isocyanate or an yneisocyanate to form the corresponding polyene.The general procedure and stoichiometry of this synthesis route issimilar to that described for polyisocyanates in the preceding. In thisinstance, a polyol reacts with an ene-isocyanate to form thecorresponding polyene. It is found, however, that products derived fromthis route, when cured in the presence of high energy bombardment and apolythiol, may form relatively weak solid polythioether products. Toobtain stronger cured products, it is desirable to provide polarfunctional groupings within the main chain backbone of the polymericpolyene. These polar functional groupings serve as connecting linkagesbetween multiple repeating units in the main chain series, and serve asinternal strength-reinforcing agents by virtue of their ability tocreate strong interchain attraction forces between molecules of polymerin the final cured composition.

Polyenes containing ester groups may be formed by reacting an acid ofthe formula R {COOH),, wherein R is a polyvalent organic moiety freefrom reactive carbon-to-carbon unsaturation and n is at least 2; witheither an ene-01 or yne-ol. The reaction is carried out in an inertmoisture-free atmosphere (nitrogen blanket) at atmospheric pressure at atemperature in the range from to about 120 C. for a period of 5 minutesto 25 hours. Usually the reaction is carried out in the presence of acatalyst (p-toluene sulfonic acid) and in the presence of a solvent,e.g. benzene at refluxing temperature. The water formed is azetroped offof the reaction.

Another method of making an ester containing polyene is to react apolyol of the formula R (0'H) wherein R is a polyvalent organic moietyfree from reactive carbon-to-carbon unsaturation and n is at least 2;with either an ene-acid or an yne-acid. The reaction is carried out inthe same manner as set out above for the estercontaining polyenes. Inpracticing this latter technique, however, it may be found thatene-acids (or yne-acids) in which the one (or yne) group is adjacent toan activating polar moiety such as and the like are generally notdesirable within the scope of this invention. These activated enecompounds are very prone to selfpolymerization reactions to form vinylpolymers. Excessive amounts of self-polymerization of the ene groups isan undesirable side reaction in the present invention since the desiredpolythioether reaction products are precluded wheneverself-polymerization of the ene groups occurs. Finally, the presence ofactivated, easily self-polymerizable ene groups in the composition leadsto oxygen inhibition during curing, storage stability problems, or theneed for excessively high inhibitor concentrations.

In forming the urethane-containing polyenes of the present invention,catalytic amounts of a catalyst may be employed to speed up thereaction. This is especially true in the case where an ene-o1 is used toform the polyene. Such catalysts are well known to those in the art andinclude organometallic compounds such as stannous octoate, stannousoleate, dibutyl tin dilaurate, cobalt acetylacetonate, ferricacetylacetonate, lead naphthanate and dibutyl tin diacetate.

In summary, by admixing polyenes or polyynes containing two or morereactive unsaturated carbon-to-carbon bonds located terminal from themain chain with a polythiol containing two or more thiol groups permolecule and thereafter exposing said liquid mixture to high energybombardment, there is provided an essentially odorless solid elastomericor resinous polymeric product.

Polythiol as used herein refers to simple or complex organic compoundshaving a multiplicity of pendant or terminally positioned -SH functionalgroups per average molecule.

On the average the polythiol must contain 2 or more -SH groups/moleculeand have a viscosity range of essentially '0 to million centipoises (cm)at 70 C. as measured by a Brookfield viscometer either alone or when inthe presence of an inert solvent, aqueous dispersion or plasticizer.Operable polythiols in the instant invention usually have molecularweights in the range about 50 to about 20,000, and preferably from aboutto about 10,000.

The polythiols operable in the instant invention may be exemplified bythe general formula Rg'SH) where n is at least 2 and R is a polyvalentorganic moiety free from reactive carbon-to-carbon unsaturation. Thus Rmay contain cyclic groupings and hetero atoms such as N, -P or O andprimarily contains carbon-carbon, carbonhydrogen, carbon-oxygen; orsilicon-oxygen containing chain linkages free of any reactivecarbon-to-carbon unsaturation.

One class of polythiols operable with polyenes to obtain essentiallyodorless polythioether products are esters of thiol-containing acids ofthe formula general structure:

I 0 Rm\ 0 i )R -SH) where R and R are organic moieties containing noreactive carbon-to-carbon unsaturation, and n is 2 or greater.

Certain polythiols such as the aliphatic monomeric polythiols (ethanedithiol, hexamethylene dithiol, decamethylene dithiol,tolylene-2,4-dithiol, and the like), and some polymeric polythiols suchas a thiol-terminated ethylcyclohexyl dimercaptan polymer, and the like,and similar polythiols which are conveniently and ordinarily synthesizedon a commercial basis, although having obnoxious odors, are operable butmany of the end products are not widely accepted from a practical,commercial point of view. Examples of the polythiol compounds preferredbecause of relatively low odor level include but are not limited toesters of thioglycolic acid (HS-CH2COOH), a-mercaptopropionic acid(HS-CH (CH3) )COOH and fi-mercaptopropionic acid (HS-CH CH COCH) withpolyhydroxy compounds such as glycols, triols, tetraols, pentaols,hexaols, and the like. Specific examples of the preferred polythiolsinclude but are not limited to ethylene glycol bis (thioglycolate),ethylene glycol bis (fl-mercaptopropionate), trimethylolpropane tris(thioglycolate), trimethylolpropane tris (B-mercaptopropionate),pentaerythritol tetrakis (thioglycolate) and pentaerythritol tetrakis(fi-mercaptopropionate), all of which are commercially available. Aspecific example of a preferred polymeric polythiol is polypropyleneether glycol bis (B-mercaptopropionate) which is prepared frompolypropylene-ether glycol (e.g. Pluracol P2010, Wyandotte ChemicalCorp.) and fl-rnercaptopropiom'c acid by esterification.

The preferred polythiol compounds are characterized by a low level ofmercaptan-like odor initially, and after reaction, give essentiallyodorless polythioether end products which are commercially attractiveand practically useful resins or elastomers for both indoor and outdoorapplications.

Prior to curing, the liquid polymer may be formulated for use as 100%solids, or disposed in organic solvents, or as dispersions or emulsionsin aqueous media.

The curable liquid polymer compositions prior to curing may readily bepumped, poured, siphoned, brushed, sprayed, doctored, or otherwisehandled as desired. Following application, curing in place to a solidresin or elastomer may be effected very rapidly as desired bymanipulation of the compounding ingredients and the intensity of highenergy curing.

The liquid polythioether-forming components and compositions, prior tocuring, may be admixed with or blended with other monomeric andpolymeric materials such as thermoplastic resins, elastomers orflhermosetting resin monomeric or polymeric compositions. The resultingblend may be subjected to conditions for curing or co-curing of thevarious components of the blend to give cured products having unusualphysical properties.

Although the mechanism of the curing reaction is not completelyunderstood, it appears most likely that the curing reaction may beinitiated by most any high energy generator which dissociates orabstracts a hydrogen atom from an SH group, or accomplishes theequivalent thereof. Generally the rate of the curing reaction may beincreased by increasing the temperature of the composition at the timeof initiation of cure. In many applications, however, the curing isaccomplished conveniently and economically by operating at ordinary roomtemperature conditions. Thus for use in elastomeric sealants, it ispossible merely to expose the polyene and polythiol admixtures to highenergy bombardment under ambient conditions and obtain a cured solidelastomeric or resinous product.

The present composition may be cured by high energy bombardment such asby nuclear particles, as well as high energy radiation having awavelength shorter than about 2,000 A.

A class of high energy bombardment includes energetic electrons such asthose derived from isotopes such as strontium-90, or intense electronbeams produced by particle accelerators. Electron beam curing is mostuseful in applications where very rapid and economical rates aredesired. By way of example, in some systems curing periods of less thanabout one second may be experienced using a total radiation dose of lessthan about 0.25 megarad.

A second class of high energy bombardment includes X-rays. X-rays areuseful in that relatively thick sections of curable composition may bepenetrated during the curing process.

A third class of high energy bombardment includes energetic radiationderived primarily from radioactive isotopes, chemonuclear methods andthe like. Included in this class are ionizing radiation particles suchas alpha rays, neutrons, protons and the like as well as gammaradiation.

Conventional curing inhibitors or retarders which may be used in orderto stabilize the components or curable compositions so as to preventpremature onset of curing may include hydroquinone; p-tert.-butylcatechol; 2,6-ditert. butyl p-methylphenol; phenothiazine; N-phenyl-Z-naphthylamine; inert gas atmospheres such as helium, argon, nitrogen andcarbon dioxide; vacuum, and the like.

To obtain the maximum strength, solvent resistance, creep resistance,heat resistance and freedom from tackiness, the reaction componentsconsisting of the polyenes and polythiols of this invention areformulated in such a manner as to give solid, crosslinked, threedimensional network polythioether polymer systems on curing. In order toachieve such infinite network formation the individual polyenes andpolythiols must have a functionality of at least 2 and the sum of thefunctionalities of the polyene and polythiol components must always begreater than 4. Blends and mixtures of the polyenes and the polythiolscontaining said functionality are also operable herein.

The compositions to be cured, i.e., (converted to solid resins orelastomers) in accord with the present invention may, if desired,include such additives as antioxidants, synergistic agents, dyes,inhibitors, fillers, pigments, antistatic agents, fiame-retardantagents, thickeners, thixotropic agents, surface-active agents, viscositymodifiers,

extending oils, plasticizers, tackifiers and the like within the scopeof this invention. Such additives are usually preblended with thepolyene or polythiol prior to or during the compounding step. Operablefillers include natural and synthetic resins, carbon black, glassfibers, wood flour, clay, silica, alumina, carbonates, oxides,hydroxides, silicates, glass flakes, glass beads, borates, phosphates,diatomaceous earth, talc. kaolin, barium sulfate, calcium sulfate,calcium carbonate, antimony oxide and the like. The aforesaid additivesmay be present in quantities up to 500 parts or more per parts polymerby weight and preferably about 0.0005 to about 300 parts on the samebasis.

The compounding of the components prior to curing may be carried out inseveral ways. For example, the polyene, the polythiol and any otherinert additives may be admixed and charged to an aerosol can, drum,tube, or cartridge for subsequent use.

Another useful method of compounding is to prepare in an ambientatmosphere by conventional mixing techniques but in the absence of highenergy bombardment, a composition consisting of polyene, antioxidant (toinhibit spontaneous oxygen-initiated curing), polythiol and other inertadditives. This composition may be stored in the dark for extendedperiods of time, but on exposure to high energy bombardment will curecontrollably and in a very short time period to solid polythioetherproducts.

The mole ratio of ene/thiol for preparing the curable composition isfrom about 0.2/1 to about 5/ 1, and desirably about 0.75/1 to about1.5/1.

The following examples will aid in explaining, but should not be deemedas limiting, the instant invention. In all cases, unless otherwisenoted, all parts and percentages are by weight.

FORMATION OF POLYENE PREPOLYMER Example 1 458 g. (0.23 mole) of acommercially available liquid polymeric diisocyanate sold under thetradename Adiprene L-IOO by E. I. du Pont de Nemours & Co. was chargedto a dry resin kettle maintained under a nitrogen atmosphere andequipped with a condenser, stirrer, thermometer, and gas inlet andoutlet. 37.8 g. (0.65 mole) of allyl alcohol was charged to the kettleand the reaction was continued for 17 hours with stirring at 100 C.Thereafter the nitrogen atmosphere was removed and the kettle wasevacuated 8 hours at 100 C. 50 cc. dry benzene was added to the kettleand the reaction product was azeotroped with benzene to remove theunreacted alcohol. This allyl terminated liquid prepolymer had amolecular weight of approximately 2100 and will be referred to asPrepolymer A hereinafter.

Example 2 400 g. (0.2 mole) of "Adiprene L-100 was charged to a dryresin kettle maintained under nitrogen and equipped with a condenser,stirrer, thermometer and gas inlet and outlet. 25.2 g. (0.43 mole) ofpropargyl alcohol (HCEC-CHgOH) was added to the kettle and the reactionwas continued with stirring for 18 hours at C. Thereafter the nitrogenatmosphere was removed and the kettle was evacuated 16 hours at 100 C.followed by azeotropic distillations with 50 cc. water and then 50 cc.benzene to remove any excess propargyl alcohol. This HCEC- terminatedliquid propolymer had a viscosity of 27,500 centipoises at 70 C. and amolecular weight of 2100 and will be referred to as Prepolymer Bhereinafter.

Example 3 1 mole of commercially available poly(ethylene ether) glycolhaving a molecular weight of 1450 and a specific gravity of 1.21 wascharged to a resin kettle maintained under nitrogen and equipped with acondenser, stirrer,

thermometer and a gas inlet and outlet. 2.9 g. dibutyl tin dilaurate asa catalyst was charged to the kettle along with 2 molestolylene-2,4-diisocyanate and 2 moles of allyl alcohol. The reaction wascontinued with stirring at 60 C. for 2 hours. Thereafter a vacuum of 1mm. was applied for 2 hours at 60 C. to remove the excess alcohol. ThisCH =CH- terminated prepolymer had a molecular weight of approximately1950 and will hereinafter be referred to as Prepolymer C.

Example 4 1 mole of a commercially available poly(propylene ether)glycol having a molecular weight of about 1958 and a hydroxyl number of57.6 was charged to a resin kettle equipped with a condenser, stirrer,thermometer and a gas inlet and outlet. 4 g. of dibutyl tin dilaurate asa catalyst was added to the kettle along with 348 g. (2.0 moles) oftolylene-2,4-diisocyanate and 116 g. (2 moles) of allyl alcohol. Thereaction was carried out for minutes at room temperature under nitrogen.Excess alcohol was stripped from the reaction kettle by vacuum over a 1hour period. The thus formed CH =CH-- terminated liquid prepolymer had amolecular weight of approximately 2400 and will hereinafter be referredto as Prepolymer D.

Example 5 750 g. of a N-containing tetrol (hydroxyl functionality=4)available from Wyandotte Chemicals Corp. under the tradename TetronicPolyol 904 having a M.W. of 7,500 was placed in a reaction vessel heatedat 110 C. The fiask was maintained under vacuum for 1 hour. Then, underan atmosphere of nitrogen, 0.1 cc. dibutyl tin dilaurate was added andthe flask was cooled to 50 C. Now 18.3 g. allyl isocyanate was addedslowly, maintaining the temperature at about 95 C. for about 1 hourafter the addition was completed. The thus formed polymeric polyene(i.e., Prepolymer E hereinafter) had a theoretical allyl functionalityof 2.2, a theoretical hydroxyl functionality of 1.8, and a calculatedmolecular weight of about 7,683.

Example 6 To a resin kettle maintained under a nitrogen atmosphere andequipped with a condenser, stirrer, thermometer and gas inlet and outletwas added 843 g. of a commercially available liquid diisocyanateprepolymer sold under the tradename Multrathane F-196 by Mobay ChemicalCo., said prepolymer having a molecular weight of about 1680 and anavailable isocyanate content of 4.7- 5.2%. 87 g. (1.5 moles) of allylalcohol was added to the kettle and the reaction was continued for 18hours at 140 C. with stirring. Thereafter the nitrogen atmosphere wasremoved and the kettle was evacuated for 22 hours at 100 C. 50 cc. ofdry benzene was added to the kettle and the reaction product wasazeotroped therewith to remove any unreacted alcohol. This CH =CH-terminated liquid prepolymer had a viscosity of 25,000 centipoises at 70C. and a molecular weight of approximately 1800 and will be referred toas Prepolymer F hereinafter.

Example 7 678 g. (0.34 mole) of a commercially available poly (propyleneether) glycol sold under the tradename NIAX by Union Carbide Co. andhaving a molecular weight of about 2025 was degassed for 2 hours at 100C. and thereafter charged to a resin kettle maintained under a nitrogenatmosphere and equipped with a condenser, stirrer, thermometer and gasinlet and outlet. 118 g. (0.68 mole) of tolylene 2,4 diisocyanate wascharged to the kettle and the reaction was heated with stirring for 2%hours at 120 C. After cooling, 58 g. (1.0 mole) of allyl alcohol wasadded to the kettle and the mixture wasrefiuxed at 120 C. for 16 hoursunder nitrogen. Excess allyl alcohol was removed overnight by vacuum atC. Half of the allyl terminated liquid prepolymer having a viscosity of19,400 cps. at 30 C. as measured on a Brookfield viscometer was removedfrom the kettle and will be referred to hereinafter as Prepolymer G. Theother half portion of the prepolymer was combined with 50 cc. of drybenzene and azeotroped overnight following which excess benzene waspulled out under vacuum for 5 hours at 120 C. This portion of theallyl-terminated liquid prepolymer had a viscosity of 15,600 cps. at 70C. as measured on a Brookfield viscometer and a molecular weight ofapproximately 2500 and will hereinafter be referred to as Prepolymer H.

(propylene ether) glycol sold under the tradename Pluracol P 2010 byWyandotte Chemical Co. was degassed at room temperature for 3 hours andthen charged to a dry resin kettle maintained under a nitrogenatmosphere and equipped with a condenser, stirrer, thermometer and gasinlet and outlet. 132 g. (0.76 mole) of tolylene-2,4-diisocyanate wascharged to the kettle and the kettle was heated for 2 hours at 120 C.with stirring under nitrogen. After cooling, 5-8 :g. (1.0 mole) of allylalcohol was added and the mixture was refluxed at 120 C. overnight.Excess allyl alcohol was stripped by vacuum overnight at 120 C. The thusformed allyl terminated liquid prepolymer had a viscosity of 15,000 cps.as measured on a Brookfield viscometer at 70 C. and a molecular weightof approximately 2500 and will hereinafter be referred to as PrepolymerI.

Example 9 To a 1 liter resin kettle equipped with stirrer, thermometer,gas inlet and outlet and heated to a temperature of 50 C. was charged610 g. (0.2 mole) of poly(tetramethylene ether)glycol, commerciallyavailable from Quaker Oats Co. and having a hydroxyl number of 37.1along with 0.3 g. dibutyl tin dilaurate. The temperature of the kettlewas raised to C. and the contents were freed of water under 1 millimetervacuum for 1 hour. The resin kettle was cooled to 60 C. and the systemwas placed under a protective atmosphere of nitrogen throughout theremainder of the reaction. 25.2 g. of allyl isocyanate (0.4 mole) wasadded dropwise to the kettle at such a rate as to maintain thetemperature at 60 C. When the NCO content dropped to 0.54 mg./g., 1 mm.vaccum again was applied and the: system was heated at 70 C. for onehour. The thus formed polymer product was a solid at room temperaturebut at 50 C. is clear and pourable. The polymer product had a viscosityof 1,800 centipoises at 70 C. as measured on a Brookfield viscometer andan average molecular weight of approximately 3200.

Example 10 To a 1 liter resin kettle equipped with stirrer, thermometer,gas inlet and outlet was charged 591 g. (0.30 mole) of a poly(propyleneether) glycol commercially available from Union Carbide under the tradename PPG 2025 and 0.3 g. of dibutyl tin dilaurate. The kettle was heatedto 110 C. and the contents were freed of water under 1 mm. vacuum for 1hour. The kettle was cooled to 25 C. and the system was placed under aprotective atmosphere of nitrogen throughout the remainder of thereaction. 53.1 ml. (49.8 g., 0.6 mole) of allyl isocyanate commerciallyavailable from Chemetron Corp. was added to the system. An exothermcarried the temperature to 45 C. in 22 minutes. After 60 minutes, theNCO content '(as determined by titration) was 0.04 mg./g. The system wasplaced under 1 mm. vacuum and heated to 70 C. to remove traces ofunreacted allyl isocyanate. The resultant polymer product had aviscosity of 600 centipoises at 30 C. as measured on a Brookfieldviscometer and an average molecular weight of approximately 2200.

The next two examples show a method of preparing the polyenes of theinstant invention by dehydration of polyether glycols.

Example 11 100 g. of poly(propylene ether) glycol commercially availablefrom Union Carbide under the trade name PPG 2025 was poured through ahot tube filled with aluminum oxide at such a rate that the entirereaction took place in 2 hours. The tube was 1 in diameter with thereaction zone 1 ft. long and completely enclosed within a tube furnace.The alumina catalyst was 10-18 mesh and was maintained at 350 C. using aLindberg Hevi-Duty tube furnace. The tube was fitted with a droppingfunnel and a nitrogen inlet at the top. Nitrogen pressure was kept onthe system throughout the reaction. The product collected from thebottom of the tube was analyzed for unsaturation by. the mercuricacetate titration method and was found to have 100% of the theoreticalamount of unsaturation expected after dehydration of both terminalhydroxyl groups of the poly(propylene ether) glycol. The polyene producthad a viscosity of 125 cps. at 70 C. and an average molecular weight ofapproximately 2000.

Example 12 1 kilogram of poly(propylene ether) glycol commerciallyavailable from Union Carbide under the trade name PPG 2025 was heated to120 C. in a round bottom flask. To this was added 120 ml. excess) ofacetic anhydride at such a rate that the temperature of the mixture waskept at 120140 C. Following the addition, the mixture was heated at 140C. for 4 hours. It was then cooled and diluted with an equal volume ofchloro form, washed with 10% aqueous sodium carbonate, then with water.The organic layer was separated and the chloroform was removed bydistillation. Infrared analysis of the purified material showed it to bethe diacetate of the poly(propylene ether) glycol with no residualhydroxyl groups.

100 g. of this diacetate was put through the hot tube as in Example 11except that the packing was glass helices instead of alumina and thetemperature was 375 C. The product contained 64% of the theoreticalamount of unsaturation expected after the elimination of acetic acidfrom both terminal acetoxy groups of the poly- (propylene ether) glycoldiacetate.

Example 13 114 g. of hexol sold under the trade name Niax Polyol LS-490by Union Carbide Chemicals Co. having a molecular weight of 684 wascharged to a 1 liter 4 neck flask and heated to 110 C. under vacuum andnitrogen for 1 hour. It was then cooled to approximately 60 C. whereat0.1 cc. of dibutyl tin dilaurate was added followed by slowly adding 83g. (1 mole) of allyl isocyanate to keep the temperature in the range70-80 C. during the addition. After addition, the reaction was allowedto continue for 1 hour at 70 C. The polymeric hexaene product obtainedhad an average molecular weight of approximately 1200 and a viscosity of300 centipoises at 70 C.

16 Example 14 To a 1 liter 4 neck flask was charged 300 milliliters ofdimethylformamide, 35 g. of tolylene-2,4-diisocyanate and 0.1 cc. ofdibutyl tin dilaurate. A mixture of 11.6 g. of allyl alcohol and 22.8 g.of hexol commercially available from Union Carbide Chemical Co. underthe trade name Niax Polyol LS-490 having a molecular weight of 684 wasslowly added to the flask. Temperature was kept at approximately 65 C.during the addition and for a period of 1 hour. The polymeric productobtained had an average molecular weight of approximately 2100.

Example 15 To a 1 liter 4 neck flask was charged 100 cc. ofdimethylformamide, 100 g. of tolylene-2,4-diisocyanate and 0.1 cc.dibutyl tin dilaurate. 58 g. of hexol, i.e. Niax Polyol LS-490 by UnionCarbide and 34 g. of allyl alcohol were mixed together and addeddropwise to the flask. Before the addition to the flask was completed,the reaction, which was exothermic, gelled and the addition wasdiscontinued.

A comparison of Examples 13, 14 and 15 shows that Example 13 is animprovement over Examples 14 and 15 in that it allows one to formpolymer without the necessity of a solvent. A comparison of Examples 14and 15 shows that when starting with a highly functional polyol usingthe diisocyanate/allyl alcohol technique one must operate in dilutesolution to avoid premature crosslinking (i.e., gelation) which rendersthe polyene product useless as a curable liquid prepolymer. This problemis avoided completely by using the unsaturated monoisocyanate techniqueillustrated in Example 13.

Example 16 In a 1 liter, 4 neck flask 220 g. of hexol commerciallyavailable from Union Carbide Chemicals Co. under the trade name NiaxPolyol LS-490 (0.32 mole) and 0.1 cc. of dibutyl tin dilaurate washeated to 110 C. under vacuum for 1 hour. After cooling in nitrogen toapproxi mately 60 C., g. of allyl isocyanate was added to the flask bymeans of a dropping funnel. The exothermic reaction produced atemperature of C. When the addition was complete the reaction wascontinued at 70 C. for 1 hour. The resulting triene polymer product hadan average molecular weight of approximately 950 and a viscosity of 300centipoises as measured on a Brookfield viscometer at 70 C.

Example 17 To a 1 liter 4 neck flask was charged 300 g. of a polyesterdiol (molecular weight 3232) sold under the tradename RC Polyester S10135 by R. C. Division, Hooker Chemical Corp. and 0.1 cc. of dibutyltin dilaurate. The flask was heated to C. of dibutyl tin dilaurate. Theflask was heated to 110 C. under vacuum and maintained thereat for 1hour. The flask was cooled to approximately 60 C., nitrogen wasadmitted, and 7.7 g. allyl isocyanate and 8.1 g. oftolylene-2,4-diisocyanate was added by means of a dropping funnel to thereaction at a moderate rate. A maximum temperature of 90 C. was needed.When the addition was complete the reaction was allowed to continue at70 C. for 1 hour. The thus formed solid polymeric product had an averagemolecular weight of approximately 6800 and a viscosity of 13,600centipoises when measured on a Brookfield Viscometer at 70 C.

l '7 Example 18 To a 1 liter 4 neck flask heated at 110 C. was charged808 g. of a polyester diol (having a molecular weight 3232) sold underthe tradename RC Polyester S 101-35 15 minutes. A maximum temperature of90 C. Was pro- 5 duced by the exothermic reaction. The polymeric productobtained was a solid at room temperature but liquid at 70 C. The producthad an average molecular weight of approximately 10,500 and a viscosityof 270,000 centipoises at 70 C.

Example 19 Following the procedure of Example 12 and using necsaryreactants, a polyene of the following formula was Example 20 Followingthe procedure of Example 3, and using nec- 18 Example 22 Following theprocedure of Example 3, and using necessary reactants, a polyene of thefollowing formula was prepared:

Example 23 Following the procedure of Example 3, and using necessaryreactants, a polyene of the following formula was prepared:

essary reactants, a polyene of the following formula was 40 prepared:

Example 21 A crotyl-terminated polyurethane which contains two reactivedouble bonds per average molecule in a near terminal position wasprepared following the general procedure of Example 3. The resultingpolymeric polyene 65 was found to have the following formula:

60 Examples 24-42 Following the general procedure of the prior examples,and using the necessary reactants, a series of polyenes having theformula:

XULB -10 o a o NH-Ji-{mwHroHi o -N CH3 flu TABLF-Continno(l Ex. Na.Component [A] Component [13] Component [X] 32 O N HO-OH CH=-I|-ICH HO--CFaGFr-C-OH OH H CH3 HOSi-OH Tetrafiuorosucclnic acid, 10 molesDiphenylsllanediol, 9 moles N-12neth1y1-N-viny1 ethanolamlne,

mo es 1,2cyc10hexa11edlo1, 5 moles Lfi-naphthalene dllsocyanate, 6 moles2- (2-1iyrldy1) -ally1 alcohol C O 0 H Propylene glycol, 6 molesIsophthallo acid, 6 moles 3-phenyl-ally1 lsocyanato, 2 moles CH OCN- s-cm -Nco l a O CN-CHz-C=CH:|

Dipheny lsllanediol, 6 moles Methyhn bisloyclohexyl isocyanate), 52-methyl-allyl isocyanate, 2 moles mole as E if l zN-\CH2 H2NH HaCHaNH:None OCN \GHrCEL-CH,

an a

Poly (ethylene lmlne), 1 mole Q-decenyl isocy anate, 3 moles A} 2 ocNomnco Dibrornoneopentyl glycol-DOW SA-1l38,

3 moles Hexamethyleno dllsocyanate, 4 moles 2-ohloro-2-propen-1-ol, 2moles H N-CH: 2N112 1,4-di(amlnomethy1) cyclohexane, 10 moles Adipicacid, 11 moles 2-(zP-natgmxybenzyl) allyl amine,

39...- HO-CF OF OH 00011 a r- HOCH;OCH=CH;

Tetrafluoroethylene glycol, 3 moles Trimellltic anhydride, 1 molerlnyloxybenzyl alcohol, 3 moles TABLE-Continued 40.-.. N ocmcmncrr=om HO-CII;CHzG -H 1 230 I I Poly(ethylene ether) glycol, 1 mole4-pentenylisocyanate, 2 moles 41-... Pluraeo1 208 DDI DiisocyanateCHaOCHzCE=CH1 Phosphorus-based polyol-Wyandotte Chem. Co., 1 moleno-cm-b-cim Hi CHaCH=OHz 1,1,l-trimethylolpropanedlallyl ether,

2 moles 42...- CH) CH: O

no-izrr-cm emcee-on OCN CH CH%TCHPNOO HOCHZCH:-NC/ on u-crncm-n H n-Jinno-cn-c omen-on H:

N,N,N ,N-tetrakls (2-hydroxypropyl -ethyl- Ene iziiaminewyandotte Co.,Quadro1,

mo e

2,7411 (lsoeyanato)-heptane, 4 moles N- (2-fury1) -N-vlny1 ethanolamlne,

4 moles HIGH ENERGY CURING PROCESS Examples 43-47 grams of an admixtureof Prepolymer I polyene (Example 8), pentaerythritoltetrakis(/3-mercaptopropionate), a commercially available polythiol fromCarlisle Chemical Company sold under the trade name Q-43, said admixturebeing in the enezthiol mole ratio of 1/1, respectively, were placed in ashallow aluminum dish to a depth of about 250 mils. The dish containingthe sample was placed on a conveyor belt at ambient temperature, underan atmosphere of N and passed under the electron beam of a 2 m.e.v.electron accelerator manufactured by High Voltage Engineering Co. ofBurlington, Mass. The conveyor belt was adjusted to travel at a rate of18.3 inches/minute, which gives a 3- second exposure to the electronbeam. The total dosage up to 1 Mrad was controlled by adjusting the beamcurrent. Above 1 Mrad total dosage, the number of passes was increaseduntil the desired dosage was obtained. The results are shown below:

HIGH ENERGY RADIATION CURING RESULTS (N1 atmosphere) Total Totalradiation exposure dosage, Shore A Example number time, sec. Mradshardness 1 Bottom surface was tacky.

Example 43 was repeated except that the polyene used was the hexaenefrom Example 13. The sample was cured completely through the entirethickness at the 0.1 Mrad total dosage. This sample remained entirelycolorless after 48 hours exposure to UV light in the Fade-O-meter.

Examples 49-5 2 Examples 43-46 were repeated except that the electronbeam irradiation curing was carried out in an atmosphere of air. Theresults were for all practical purposes the same as those observed inthe inert nitrogen atmosphere.

Examples 53-56 Example 46 was repeated except that curing was done inair and polyene Prepolymer I was replaced by an equivalent amount ofeach of the following polyenes: Prepolymer B, Prepolymer C, PrepolymerE, and Prepolymer A. Each of the products was cured to solid productsunder the conditions used.

Examples 57-58 Example 46 was repeated except that the samples werecured in air, the polythiol was trimethylolpropane tris (thioglycolate),the polyene was the structure from Example 30, and the one/thiol moleratio was 0.75/ 1.0 and 1.4/1.0, respectively.

Example 59 Example was repeated except that the samples were irradiatedin air and the polythiol was an equimolar mixture of pentaerythritoltetrakis(thioglycolate) and ethyl ene glycol bis(S-mercaptopropionate).The samples cured to a solid under the conditions used.

Examples 60-67 Example 44 was repeated except that the curing was donein air and the polyene was each of the following: glycerol trioleate;diallyl phthalate; diallyl amine; diallyl adipate; polyene from Examples24, 36, 38, 39. Similar results were experienced.

Example 68 1.5 moles of fi-mercaptopropionic acid, 0.5 mole of acommercially available poly(propylene ether) glycol sold under thetradename Pluracol 1 -2010 by Wyandotte Chemical Corp. and 0.1 g.p-toluenesulfonic acid and 50 ml. benzene were charged to a resin kettlemaintained under a nitrogen atmosphere and equipped with a condenser,stirrer, thermometer and gas inlet and outlet. The mixture was heatedand the benzene-water azeotrope was collected. The actual amount ofwater collected amounted to 17.5 g. The reaction was vacuum-stripped forseveral hours at 70 C. to remove benzene. The resulting polythiolpolymer had a molecular weight of about 2210- 2230 and an averagefunctionality of 2 and was collected for use herein.

659 g. (0.145 mole of a poly(propylene ether) triol commerciallyavailable from Wyandotte Chemical Corp. under the tradename Pluracol TPE4542 having a molecular weight of about 4500 and a hydroxyl number of37.1, and 0.3 g. of dibutyl tin dilaurate were charged to a resin kettlemaintained under a nitrogen atmosphere and equipped with a condenser,stirrer, thermometer and gas inlet and outlet. The reactants weremaintained at 110 C. for 1 hour and then cooled under nitrogen to roomtemperature. 25.2 g. (0.435 mole) of allyl alcohol was added to thekettle followed by 75.7 g. (0.435 mole) of an -20% isomer mixture oftolylene-2,4-diisocyanate and tolylene 2,6-diisocyanate respectivelysold under the tradename Mondur TD 80. The temperature reached 55 C. in6 minutes. A sample was titrated for NCO resulting in 6.02 mg. NCO/ g.after 20 minutes. After 1 hour the NCO titration showed 0.997 mg. NCO/g. The polyene polymer had a molecular weight of about 5200 and anaverage functionality of 3 and was vacuum stripped at 70 C. for 1 hourand then collected. 0.003 mole of the polythiol polymeric materialformed supra was charged to a 2 oz. glass jar along with 0.002 mole ofthe allyl-terminated polyene polymer formed herein along with 0.085 gramof Irganox 1076 (a phenolic antioxidant sold commercially by GeigyChemical Co.), 1.7 grams of TiO pigment and 1.7 grams of Emtal talc(available from Eastern Magnesia Talc Co., Burlington, Vt.). Theresulting composition was thoroughly mixed by stirring, and was thenexposed to electron bombardment under the conditions of Example 59. Thecomposition was cured to a solid product.

Example 69 10 grams of Prepolymer E from Example were added to each ofthree 2 oz. jars. To one of the jars was added 3 ml. of benzenecontaining 0.5% based on the weight of the repolymer of an antioxidantsold under the trade name Santonox commercially available from MonsantoChemical Co. To another of the jars containing Prepolymer E was added 3ml. of benzene containing 0.5% based on the weight of the prepolymer ofan antioxidant sold under the trade name Dalpac PG" commerciallyavailable from Hercules Powder Co. To the third jar was added 3 ml. ofbenzene as a control. To blend the components the jars were heated in aforced draft oven set at 150 C. for 25 minutes with frequent stirring.The jars were withdrawn from the oven and 1.3 grams oftrimethylolpropane tris(,B-mercaptopropionate) were added to each of thejars and curing was initiated indoors under ambient conditions. Thecontrol run, without any antioxidant present, cured within /2 hour to asolid elastomerio polymer product. The example containing Dalpac PGcured to a solid polymer product after 12 days whereas the samplecontaining Santonox required more than 2 weeks before a solidself-supporting cured polymeric product resulted.

The polyenes used in the instant invention may be used as blends ormixtures of monoenes or polyenes having the same or differentfunctionalities so long as the average functionality of the blend ormixture is at least 2. Similarly, the polythiols used herein may be usedas blends or mixtures of monothiols or polythiols having the same ordiflerent functionalities as long as the average functionality of theblend or mixture is at least 2.

The polyene/polythiol mole ratio is selected so as to provide a solidfinal cured product, i.e., one that is nonfiowing and structurallyself-supporting under ambient conditions. in typical cases, as shown bythe examples, this ratio can be about 0.2 to 5 moles thiol groups permole ene groups. In general, the more ratios significantly above orbelow I tend to give a high proportion of chain extension or graftingwhereas mole ratios near 1 give predominantly chain extension andcrosslinking. Occasionally, however, ratios necessary to give a solid asaforesaid may lie outside the stated range, and experimentation may benecessary to determine a. suitable ratio to give a solid. Thisexperimentation is easily carried out and offers no difficulties tothose skilled in the art.

The following examples show the use of the novel thiol ethers asadhesives, coatings, sealants and molded objects.

Example The following formulations were made up:

Formulation Ingredients No. I (parts) No. II (parts Prepolymer D fromExample 4 100 100 T10 (pigment) 4 4 60 85 26 0 The above formulationswere briefly admixed for homogeneity and thereafter high energy cured bythe conditions of Example 59. Both samples cure to a solid, tack-freeelastomeric sealant under the conditions used.

Example 71 10 grams of Prepolymer D were charged to a 2 oz. glass jaralong with 0.7 gram of ethylene glycol bis(mercaptopropionate) and 2.2grams pentaerythritol tetrakis- (mercaptopropionate). The reactants werewell mixed and then placed between two pieces of aluminum foil, each of5 mil thickness. The aluminum foil was pressed together by hand toinsure good contact, and then passed under the electron beam using theconditions of Example 59. An attempt was made to pull the aluminum foilapart. The aluminum foil tore before the adhesive bond was destroyed.

Example 72 50 grams of Prepolymer H along with 5.0 grams ofpentaerythritol tetrakis(mercaptopropionate) were stirred togetherbriefly in a glass jar and then poured into an aluminum mold in theshape of a shallow dish. The mold and contents were exposed to theelectron beam under the conditions of Example 59, after which time themold was torn away from the molded article which had set to a solid inthe exact shape of the mold.

Example 73 0.005 mole of Prepolymer E from Example 5 was charged to a 2oz. glass jar along with 0.0033 mole of trimethylolpropane tris(p-mercaptopropionate). The reactants were stirred briefly and thencoated onto a piece of 17 pt. clay coated paper by means of a No. 10rod. The coated paper was then placed under the electron beam under theconditions of Example 59. A clear solid coating resulted on the paper.The same technique was used successfully to coat cellophane, aluminumfoil, steel plate stock, Mylar polyester film, plywood, and a concreteblock of the type used in building construction.

EXAMPLES 74-88 Electron 2 beam (EB) Shore A Sample P lydosage, hardnessnumber Polyene Source of polyenc thiol l Inegarads (EB cured) 7t1,2,4-triviny1cyclohexane Aldrich Chem. 00., Inc. 3 75--. Lfi-hexadienc....d0 5 76 Diallyl terephthalate- Chemicals Procureme 7g 77--. Diallyloxalate so 78... Diallyl 1,4-eyclohexanedicarboxylate-. .d0 Q-43 70 79Tetraallyl orthosilicate Aldrich Chem. 00., Inc Q,43 72 80 Diallyldiphenylsilane Chemicals Procurement Lab. Inc-.. Q43 75 81--. Diallylallyl phosphonate. Aldrich Chem. 00., Inc Q43 3 82. Diallyl phenylphosphite- K. dz K. Laboratories, inc. 60 83 N,N-dial1y1iormamideAldrich Chem. 00., Inc 53 84- N,N,N,N-tetraallylmethylene aminMonomer-Polymer Labs, Inc 70 85 4-vinyl-1-cyclohexcne K. dz K.Laboratories, Inc. 60 86 Diethyleneglycol divinyl ether (.9 mole)diallylamine Polyscienees, Inc 20 87--. Triallyl phosphate AldrichChemical Co., Inc 20 88 N,N-diallyl piperazine Chemicals ProcurementLab. Inc. Q-4 20 1 Q43 is pentaerythritoltetrakis(fl-mcrcaptopropionate); P-33 is trimethylolpropanetris(B-mcrcaptopropionate. The polythiol is used in the theoreticalequivalent amount based on the polyene used.

I Samples were irradiated using a Van de Greafl accelerator. Samplethickness 35-140 mils.

Example 89 916 grams (0.46 mole) of a commercially available liquidpolymeric diisocyanate sold under the trade name Adiprene L-lOO by E. I.du Pont de Nemours & Co. were charged to a dry flask maintained under anitrogen atmosphere and equipped with a condenser, stirrer, thermometerand gas inlet and outlet. 197 grams (0.92 mole) of the diallyl ether oftrimethylolpropane were charged to the vessel along with 0.56 gramdibutyltin dilaurate catalyst. The flask and contents were heated withstirring for 30 minutes at 50 C. to yield a polytetraene of about 2400M.W.

To the tetraene were added 230 grams pentaerythritol tetrakis(fl-mercaptopropionate), 18.4 grams benzophenone, 1.2 gramsdilaurylthio-dipropionate, 136 grams of dioctyl phthalate, and 1.2 gramsPlastanox 2246 (hindered phenol antioxidant sold by American CyanamidCo.). This photocurable liquid composition was cast on a glass plate ina layer 40 mils thick. It was then exposed to high energy curingaccording to the conditions of Example 43. The layer cured to a solidthrough the entire thickness under the conditions used, or at aliquid-to-solid conversion rate of over 800 mils/minute. The solidrubbery product had a Shore A hardness of 70, a tensile strength of 200p.s.i., and an elongation at failure of about 30 percent.

Example 90 An 80/20 mixture of tolylene 2,4-diisocyanate and tolylene2,6-diisocyanate (1 mole) was reacted with allyl alcohol (2 moles) underthe conditions used for the similar synthesis described in Example 89.The resulting diene (3 moles) was mixed with 2.1 moles of thetris(3-mercap topropyl) ether of tris(2-hydroxyethyl) isocyanurate.

10 grams of the above curable composition were placed in a smallaluminum mold and inserted into the exposure chamber of a Model M 38-3Gammator B laboratory irradiator (available from Radiation MachineryInc.) fitted with cesium 137-chloride as the radiation source,furnishing a nominal 0.15 megarad/hour radiation intensity of gammaradiation. After 1 hour exposure, the liquid composition was cured to acros'slinked solid having a Shore A hardness greater than 20.

Example 91 The tetraene (1 mole) from Example 41 was admixed withpentaerythritol tetrakis(fi-mercaptopropionate) (1.2 moles). A 5 gramsample of this composition was exposed to X-radiation in the GE XRD-3(air path) radiation unit. The unit was equipped with a tungsten targettube and operated at 50 kv. and 40 milliamps. The composition layercured through the entire A inch depth within minutes, or at aliquid-to-solid conversion rate in excess of mils/minute. The Shore Ahardness of the solid cured product was in excess of 50 units.

The solid cured polythioether polymer products resulting from theinstant invention have many and varied uses. Examples of some usesinclude but are not limited to adhesives; caulks; elastomeric sealants;coatings; encapsulating or potting compounds; liquid castable elasto'mers; thermoset resins; impregnants for fabric, cloth, fibrous webs andother porous substrates; laminating adhesives and coatings; mastics;glazing compounds; fiberglass reinforced composites; sizing or surfacefinishing agents; filleting compounds; cure in place gasketingcompounds; rocket fuel binders; foamable thermosetting resins orelastomers; molded articles such as gaskets, diaphragms, balloons,automobile tires, etc.

The molecular weight of the polyenes of the present invention may bemeasured by various conventional methods, including solution viscosity,osmotic pressure and gel permeation chromatography. Additionally, themolecular weight may be calculated from the known molecular weight ofthe reactants.

The viscosity of the polyenes and polythiols may be measured on aBrookfield viscometer at 30 or 70 C. in accord with the instructionstherefor.

The components to be cured may be prepared as either single-packaged ormulti-packaged liquid polymer systems which may be cured to solidpolythioether elastomers without liberating gaseous by-products whichcause bubbles and voids in the vulcanizate. Thus, there is providedcurable liquid polymer systems composed of polyenes and polythiols inwhich the components individually are storage stable and which are notsensitive to or deteriorated by traces of moisture or oxygen containinggas such as may be encountered during normal storage or handlingprocedures. Solid resinous or elastomeric products may be prepared fromflowable liquids in a system in which the rate of curing may beinhibited or retarded by the use of chemical inhibitors, antioxidants,inert atmospheres and and the like. The cured product may becharacterized as in the thermally and oxidatively stable state sincethere is no reactive carbon-to-carbon unsaturation in the main backbonechain.

As used herein the term polyene and the term polyne refers to single orcomplex species of alkenes or alkynes having a multiplicity of terminalreactive carboneto-carbon unsaturated functional groups per averagemolecule. For example, a diene is a polyene that has two reactivecarbon-to-carbon double bonds per average molecule, while a diyne is apolyyne that contains in its structure two reactive carbon-to-carbontriple bonds per average molecule. Combinations of reactive double bondsand reactive triple bonds Within the same molecule are also possiblesuch as for monovinylacetylene which is a polyeneyne under thisdefinition. For purposes of brevity all these classes of compounds arereferred to hereafter as polyenes.

In defining the position of the reactive functional carbon-to-carbonunsaturation, the term terminal is intended to mean that functionalunsaturation is at an end of the main chain in the molecule; whereas bynear terminal is intended to mean that the functional unsaturation isnot more than 10 carbon atoms and typically less than 8 carbon atomsfrom an end of the main chain in the molecule. The term pendant meansthat the reactive carbon-tocarbon unsaturation is located terminal ornear-terminal in a branch of the main chain as contrasted to a positionat or near the ends of the main chain. For purposes of brevity all ofthese positions are referred to herein generally as terminalunsaturation.

Functionality as used herein refers to the average number of ene orthiol groups per molecule in the polyene or polythiol, respectively. Forexample a triene is a polyene with an average of three reactivecarbon-to-carbon unsaturated groups per molecule and thus has afunctionality (f) of three. A dithiol is a polythiol with an average oftwo thiol groups per molecule and thus has a functionality (f) of two.

It is to be understood that the functionality of the polyene and thepolythiol component is commonly expressed in whole numbers although inpractice the actual functionality may be fractional. For example, apolyene component having a nominal functionality of 2 (from theoreticalconsiderations alone) may in fact have an eifective functionality ofsomewhat less than 2. In an attempted synthesis of a diene from a glycolin which the reaction proceeds to 100% of the theoretical value forcomplete reaction, the functionality (assuming 100% pure startingmaterials) would be 2.0. If however, the reaction were carried to onlyof theory for complete reaction, about 10% of the molecules presentwould have only one ene functional group, and there may be a trace ofmaterial that would have no one functional groups at all. Approximately90% of the molecules, however, would have the desired diene structureand the product as a whole then would have an actual functionality of1.9.

29 Such a product is useful in the instant invention and is referred toherein as having a functionality of 2.

The term reactive unsaturated carbon-to-carbon groups means groups whichwill react under proper conditions as set forth herein with thiol groupsto yield the thioether linkage as contrasted to the term unreactivecarbon-to-carbon unsaturation which means groups found in aromaticnucleii (cyclic structures exemplified by benzene, pyridine, anthracene,and the like) which do not under the same conditions react with thiolsto give thioether linkages.

Highly water-sensitive groups are intended to include, for example,isocyanate, acylhalide such as acylchloride, anhydride and the likewhich readily react with water, alcohols, ammonia, amines and the like.

Odorless has been used herein to mean the substantial absence of thewell-known offensive and sometimes obnoxious odors that arecharacteristic of hydrogen sulfide and the derivative family ofcompounds known as mercaptans.

The term non-yellowing means the substantial resistance during prolongedexposure to actinic radiation such as exposure in sunlight, to unsightlyor uncontrollable discoloration.

It is understood that the foregoing detailed description is given merelyby way of illustration and that many variations may be made thereinwithout departing from the spirit of this invention.

What is claimed is:

1. A high energy curable composition useful for obtaining an essentiallyodorless, solid polythioether, said curable composition consistingessentially of:

(A) a terminally unsaturated polyene component which comprises theformula:

wherein m is an integer of at least 2; wherein X is where f is aninteger from 1 to 9; R is a radical selected from the group consistingof hydrogen, fluorine, chlorine, furyl, thienyl, pyridyl, phenyl andsubstituted phenyl, benzyl and substituted benzyl, alkyl and substitutedalkyl, alkoxy and substituted alkoxy, cycloalkyl and substitutedcycloalkyl; said substituents on said substituted members selected fromthe group consisting of nitro, chloro, fluoro, acetoxy, acetamide,phenyl, benzyl, alkyl, alkoxy and cycloalkyl; said alkyl and alkoxyhaving from 1 to 9 carbon atoms and said cycloalkyl having from 3 to 8carbon atoms;

wherein [A] is free of reactive carbon-to-carbon unsaturation; free ofhighly water-sensitive members; and is a polyvalent chemicallycompatible member of the group consisting of carbonate, carboxylate,carbonyl, ether, silane, silicate, phosphonate, phosphite, phosphate,alkyl and substituted alkyl, cycloalkyl and substituted cycloalkyl, aryland substituted aryl, urethane and substituted urethane, urea andsubstituted urea, amine and substituted amine, amide and substitutedamide, hydroxyl, heterocyclic carbon containing radical, and mixturesthereof; said substituents on said members substituted being 30 definedabove, said component having a molecular weight in the range from about64 to 20,000; and a viscosity in the range from essentially 0 to 20million centipoises at 70 C.; and (B) a polythiol component having amolecular weight in th range from about 50 to about 20,000 of thegeneral formula:

R t-SH),

wherein R is a polyvalent organic moiety free from reactivecarbon-to-carbon unsaturation and n is at least 2, the sum of m and nbeing greater than 4, with the ene/thiol mole ratio being selected so asto provide a cross-linked solid, self-supporting cured product in thepresence of high energy bombardment selected from the group consistingof high energy radiation having a wavelength shorter than about 2,000A., and nuclear particles.

2. The composition of claim 1 wherein [A] has the formula:

a and b are integers greater than 1;

R is a member of the group consisting of hydrogen and alkyl;

R is a member of the group consisting of hydrogen, and

saturated alkyl;

R is a divalent derivative of the group consisting of phenyl, benzyl,alkyl, cycloalkyl, substituted phenyl, substituted benzyl, substitutedalkyl and substituted cycloalkyl,

wherein m is an integer of at least 2; wherein X is wherein where f isan integer from 1 to 9; R is a radical selected from the groupconsisting of hydrogen, fluorine, chlorine, furyl, thienyl, pyridyl,phenyl and substituted phenyl, benzyl and substituted benzyl, alkyl andsubstituted alkyl, alkoxy and substituted alkoxy, cycloalkyl andsubstituted cycloalkyl; said substituents on said substituted membersselected from the group consisting of nitro, chloro, fiuoro, acetoxy,acetamide, phenyl, benzyl, alkyl, alkoxy and cycloalkyl; said alkyl andalkoxy having from 1 to 9 carbon atoms and said cycloalkyl having from 3to 8 carbon atoms;

wherein [A] is free of reactive carbon-to-carbon unsaturation; free ofhighly water-sensitive members; and is a polyvalent chemicallycompatible member of the group consisting of carbonate,

carboxylate, carbonyl, ether, silane, hydroxyl, silicate, phoshonate,phosphite, phosphate, alkyl and substituted alkyl, cycloalkyl andsubstituted cycloalkyl, aryl and substituted aryl, urethane andsubstituted urethane, urea and substituted urea, amine and substitutedamine, amide and substituted amide, heterocyclic carbon containingradical, and mixtures thereof; said substituents on said memberssubstituted being defined above, said component having a molecularweight in the range from about 64 to 20,000; and a viscosity in therange from essentially O to 20 million centipoises at 70 C.; and

(B) a polythiol component having a molecular weight in the range fromabout 50 to about 20,000 of the general formula:

wherein R is a polyvalent organic moiety free from reactivecarbon-to-carbon unsaturation and n is at least 2, the sum of m and nbeing greater than 4, with the ene/thiol mole ratio being selected so asto provide a cross-linked solid, selfsupporting cured product, andthereafter (II) exposing the mixture to high energy bombardment selectedfrom the group consisting of high energy radiation having a wavelengthshorter than about 2,000 A., and nuclear particles derived fromradioactive isotopes.

6. The solid product prepared by the process of claim 5.

7. The process of claim 5 wherein high energy bombardment is energeticelectrons derived from strontium-90 or from intense electron beamsproduced by particle accelerators.

8. The process of claim 5 wherein high energy bombardment is X-rays.

9. The process of claim 5 wherein high energy bombardment is selectedfrom the group consisting of alpha particles, neutrons, and protons.

10. The process of claim 5 wherein high energy bombardment is with gammaradiation.

11; An article comprising the composition of claim 5 as a coating on asubstrate.

12. An article comprising the composition of claim 5 as an adhesivebetween two substrates. 13. An article comprising the composition ofclaim 5 D as an elastomeric sealant.

14. A shaped, molded article cast from the composition of claim 5.

15. The composition of claim 1 wherein the polyene has the formula:

where the sum of x+y+z is at least 1 and n is an integer of 0 orgreater.

16. The composition of claim 1 wherein the polyene has the formula:

where n is an integer of 0 or greater.

has the structure:

HOEC CHz where n is at least 1.

17. The composition of claim 1 wherein the polyene CECH References CitedUNITED STATES PATENTS 10/ 1968 Gourdon 260-79 10/1966 Erickson 26079 2/1968 Signouret et al. 260-79 8/ 1967 Warner 260--79 11/1968 Gmitter260=-2.5 R 1/1960 Schmitz et a1. 204-15915 RICHARD B. TURER, AssistantExaminer US. Cl. X.R.

